Is it sufficient to wash the hand with water and soap once or twice after a dog licks the hand, or is it obligatory to wash it seven times, one of them with earth? And does the prayer of one who did not wash the impurity seven times become invalidated?

That which has been defiled by a dog must be washed seven times, one of them with earth or soap. This includes clothes, hands, and other items. However, some scholars restricted this washing to a vessel licked by a dog, considering it an act of worship. Meanwhile, the Malikis hold that a dog's saliva is pure and that the washing is an act of worship specific to water vessels. Therefore, there is no need to repeat past prayers. This ruling should be observed in the future based on the preponderant opinion of generality.